Fuel pump



Patented Feb. 20, 1945 UNITED STATES PATENT mm Y FUEL PUMP Almer Newton Blazer, Mescalero, N. Mex. Application November 12, 1942, Serial No. 465,345

8 Claims.

This invention relates to a fuel pump and is more particularly adapted for use in connection with a rotary engine.

An object of the invention is the provision of a fuel pressure generator for supplying fuel to the compression chamber of an internal combustion engine under suiilcient pressure to overcome the resistance by' the compressed gases in the combustion chamber of the engine and spray the fuel into the said combustion chamber, with means for maintaining the differential pressure uniform at all times.

Another object of the invention is the provision of a. pump for forcing fuel under pressure into the combustion chamber of an internal combustion engine in which the pressure in the combustion chamber of the engine cooperates with a plunger for maintaining a sumcient pressure on the fuel to force said fuel into the combustion chamber against the pressure in said chamber until the pressure exerted by the pump on the fuel overcomes the pressure exerted by the pressure from the combustion'chamber, whence the plunger will be held inactive until a balance of pressure is obtained in the compression chamber of the pump.

A further object of the invention is the provision of a pump having a compression chamber and a plunger acting on fuel in said compression chamber for forcing the same to the combustion chamber of an internal combustion engins, said compression chamber having a flexible wall acted on by the pressure of the gases from the combustion chamber of the engine for .creating a differential pressure in the compression chamberpn the fuel, with means operated by the flexible Wall for retaining a plunger which exerts pressure on the fuel in the compression chamber in an inoperative position until the pressure in the compression chamber becomes equal to or i than the pressure exerted by the gases from the combustion chamber.

This invention will be best understood from a consideration of the following detailed descriptlon in View of the accompanying drawing forming a part of the specification; nevertheless, it is to be understood that the invention is not confined to the disclosure, being susceptible of such changes and modifications as define no material departure from the salient features of the invention as expressed in the appended claims.

In the drawing:

Fig. 1 is a plan view of a fuel pump shown in operative relation with an engine.

Fig. 2 is a. vertical section taken along the line 2-2 of Fig. 1. I

Fig. 3 is a side view in elevation of the pump, showing a latch mechanism in an inoperative position.

Fig. 4 is a similar side view and elevation showing a latch mechanism in operative relation.

Referring more particularly to the drawing, ill generally designates a rotary engine of the type referred to above, and which is adapted to be supplied fuel under a sufiicient pressure which will overcome any pressure in the combustion chamber of the engine. The engine is provided with a rotating shaft l i to which is rigidly secured a worm i2. This worm meshes with a worm gear 13 secured to a shaft 84.

A base member 20 is provided with the necessary elements for connecting the pump to the internal combustion engine 10. This base member contains a compression chamber 2! having an outlet passage 22 for fuel, and this outlet passage extends through a nipple 23 that is connected by a nut 20 to a feed pipe 25. Said feed pipe supplies fuel under pressure past a check valve 25 to a normally closed nozzle (not shown), but which is described and claimed in my copending application, S. N. 465,344, filed November 12, 1942. A diaphragm 26 forms the upper wall of the compression chamber 2! and is secured in place by means of bolts 2'3 and a flange 28 formed on the periphery of a dome-shaped member 2% which forms with the diaphragm 26 a pressure chamber 30.

A cylinder 3! is also formed in the base member 20 and has a check valve 32 where said cylinder communicates with the compression chamber 2|.

A plunger 35 is slidably mounted in a reduced portion 36 of the cylinder 3!. An enlarged square portion 3? is formed on the outer end of the pieton 35 and carries a roller 38. The portion 3'5 of the piston 35 is provided with a notch 39 for a purpose which will be presently explained. A coiled spring 30 encircles the piston 35 and has its outer endabutting the squared shoulder 3i, while the inner end abuts a packing gland M, which is screwed into an enlarged pocket at the outer end of the reduced portion 36 of the cylinder 3 An eccentric is secured to the shaft II and when operated engages the roller 38 for forcing the plunger 35 inwardly into the cylinder 3| against the tension of the spring 40. The top of the dome 28 is provided with a threaded nipple 56 which has a passage 5| leading into the chamber 30. The nipple 50 is adapted to be connected by means of a pipe 52 with the combustion chamber of the engine It] for supplying pressure to the chamber 30 for acting on the diaphragm 26.

In my co-pending application S. N. 465,344, filed November 12, 1942, there is described a carburetor which contains an injection nozzle supplying the combustion chamber of the engine with fuel under pressure. This fuel is supplied by the pump described in the present application through the passage 22. The pipe 52 which supplies pressure from the combustion chamber of the engine is designated by the general reference numeral in said co-pending application.

The cylinder 3| has an inlet passage 55 extending through a nipple 56 which is threaded to receive the usual nut 51 for connecting a pipe 58 to said nipple, and this pipe extends to the fuel supply. A check valve 55a is located in the passage 55.

A wear plate 60 is secured centrally to one face of the diaphragm 26 and is located in the cham- ,ber 30. The free end 6| of an arm 62 engages freely said plate 60. The opposite end of the arm 62 is secured to a rock shaft 63 which extends through a projection 64 of the dome 29, and a neat fit is provided by the shaft 63 in the passage in the member 64, through which the shaft extends.

A second arm 65 is rigidly secured to the projecting end of the shaft 63 and extends towards the enlargement 31 of the plunger 35, and a latch member 66 is formed on the outer free end of the arm 65 and is adapted to engage the notch 39 when the plunger 35 is moved to its inner limit of operation by the cam 45.

A spring 10 has one end provided with an opening 1| to receive a threaded bolt 12, which is screwed into the top wall 13 of the cylinder 3|. A nut 14 is threaded on to the bolt 12 and is adapted to be adjusted for raising or lowering the end of the spring 10 which has a passage H, for raising or lowering the free end 15 of said spring. It will be noted that the outer face 16 of the wall 13 is inclined and the bottom edge of the spring 70 is rounded so that the said spring may rock on the inclined wall.

The arm 65 is provided with a lug 11 which rests on the free end 16 of the spring 10, so that the free end of the member 65 will be supported by said spring for retaining the latch member 66 in disengagement with respect to the notch 39.

The operation of my device is as follows:

The passage 5| is connected with the combustion chamber of the engine I0 so that the gases from said combustion chamber will enter the pressure chamber and exert pressure on the diaphragm 26 against the pressure of the fuel in chamber 2 I.

Pressure in the chamber 2| is created by the inward movement of the plunger when the eccentric 45 acts on the roller 38 and forces the plunger inwardly into the cylinder 3| against the tension of the spring 40. When the plunger is moved to its innermost limits, it will be returned by the spring 40 as the eccentric moves away from the roller 38. The chamber 3| is supplied with fuel through the pipe 58 from a storage tank (not shown) when the plunger 35 is drawn outwardly of the cylinder 36 and on the suction stroke of said plunger.

A pressure naturally builds up in the chamber 2|, and when it becomes greater than the pressure of the gases in the chamber 30 and the tension of the spring 10 combined on the diaphragm 26, the arm 62 will be raised while the latch 66 will be lowered against the tension of the spring 10. Thus when the plunger 35 moves to its inner limits the notch 39 will fall beneath the latch 66 which will engage the notch and retain the piston 35 at its inner limits of reciprocation against the tension of the spring 40..

Now, when the pressure in the chamber 2| falls below the combined pressure in the chamber 30, and the spring 10, the diaphragm 26 will return to its normal position as shown in Fig. 2, so that the spring 10 will again raise the latch 66 away from the notch 39, and the piston will again be reciprocated by the eccentric 45. It is to be borne in mind that when the plunger 35 is retained against motion the eccentric 45 will still be operating and will engage the roller 38 periodically and force the plunger 35 slightly inwardly.

When the plunger 35 has been released, the spring 40 will return the plunger to its outward position after each actuation by the eccentric 45.

It will be seen by this construction that the diiferential pressure maintained on the fuel in the chamber 2| and the chamber 30 is determined by the adjustable tension of spring 10 at all times, regardless of the pressure on the engine.

The constant, differential pressure is essential for the vaporization of the fuel. The fuel pump provides a surplus of such pressure determined by the adjustment of the spring 10. The pressure in the combustion chamber is due to the load on the engine and is variable. The pressure in the pressure chamber 30 is equal to that in the combustion chamber at all times and varies with the load on the engine. The spring 10 is provided with its connections) to assist the pressure in 30 to resist the flexing of the diaphragm 26 to the extent due to the adjusted tension of 10, whereby the differential is constant regardless of the pressure in the combustion chamber or the compression chamber 2|. This constant differential is modified by the governor by stricture of the flow of fuel in the feed pipe as indicated by an increase or decrease in the speed of the engine with constant fuel supply.

I claim:

1. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a diaphragm therein dividing the body into a compression chamber and a pressure chamber, an arm in the pressure chamber and resting on the diaphragm, a shaft rigid with one end of the arm and projecting through the body, a latch secured to the projecting end of the shaft and extendin away from the body, a spring retaining the latch in an elevated position for forcing the arm against the diaphragm and for resisting movement of the arm by said diaphragm, means supplying fuel to the compression chamber, a plunger for exerting pressure on the fuel in the compression chamber, means for actuating the plunger in one direction to create pressure on the fuel, a spring tending to return the plunger, a pipe connecting the pressure chamber with the combustion chamber of the engine for exerting pressure on the diaphragm, means on the plunger adapted to be engaged by the latch for retaining the plunger against movement by the spring when the pressure in the compression chamber exceeds that in the pressure chamber sufliciently to move the diaphragm inwardly of the pressure chamber so that the arm will be moved and force the latch into engagement with said means.

2. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a diaphragm dividing the body into a compression chamber and a pressure chamber, a. pivoted latch located exteriorly of the body, means acted on by the diaphragm for moving the latch to an operation locking position, means for periodically creating pressure on fuel in the compression chamber and operated by the engine, means on said pressure creating means engaged by the latch for retaining the pressure creating means inactive when there is a diflerential pressure between the compression and pressure chambers, a tube connecting the pressure chamber with the combustion chamber, meanssupplying the compression chamber with fuel, and means for delivering fuel under pressure to the combustion chamber from the compression chamber.

3. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber, a pivoted latch located exteriorly of the pressure chamber, a plunger operated in one direction by the engine for creating pressure on fuel in the compression chamber and flexing said wall towards the pressure chamber, a tube connecting the pressure chamber with the combustion chamher for creating pressure on the wall in opposition to the pressure in the pressure chamber, said plunger having a notch engaged by the latch at times to retain the plunger against movement, a spring tending to return the plunger in the opposite direction, means in the pressure chamber connected to the latch and acted on by the wall when pressure became greater in the compression chamber for moving the latch to an operative position with the notch for retaining the plunger against movement by the spring until the pressure is reduced in the compression chamber and means for supplying fuel to the compression chamber.

4. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber, a pivoted latch located exteriorly of the pressure chamber, means operated in one direction by the engine for creating pressure on fuel in the compression chamber and flexing said wall towards the pressure chamber, a tube connecting the pressure chamber with the combustion chamher for creating pressure on the wall in opposition to the pressure in the pressure chamber, said pressure creating means, having a notch engaged by the latch at times to retain said means against movement, a spring tending to return the pressure creating means in the opposite direction, means in the pressure chamber, connected to the latch and acting on the wall when the pressure becomes greater in the compression chamber for moving the latch to an operative position with the notch for retaining the pressure creating means against movement-by the spring until the pressure is reduced in the compression chamber and means for supp fuel to the compression cher.

5. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber, means for supplyingpressure from the combustion chamber to the pressure chamber, means supplying the compression chamber with fuel," means exerting pressure on the fuel to flex said wall towards the pressure chamber, means operated by the flexible wall for retaining the pressure exerting means inactive when'the pressure in the compression chamber exceeds that of the pressure chamber, and a pipe in communication with the compression chamber for conducting fuel under pressure away from the chamber.

6. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber, means for supplying pressure from the combustion chamber to the pressure chamber, means supplying the compression chamber with fuel, means exerting pressure on the fuel to flex said wall towards the pressur chamber and provided with a notch, a latch operated by the flexible wall and engageable with the notch for retaining the pressure exerting means inactive when the pressure in the compression chamber exceeds'that of the pressure chamber, and a pipe in communication with the compression chamber for conducting' fuel under pressure away from the chamber.

7. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber. means for supplying pressure from the combustion chamber to the pressure chamber, meanssupplying the compression chamber with fuel, means exerting pressure on the fuel to flex said wall towards the pressure chamber and provided with a notch, a latch operated by the flexible wall and engageable with the notch for retaining the pressure exerting means inactive when the pressure in the compression chamber exceeds that of the pressure chamber, a spring for normally retaining the latch in an inoperative position, and a pipe in communication with the compression chamber for conducting fuel under pressure away from the chamber.

8. In an internal combustion engine having a combustion chamber, a fuel pump comprising a hollow body, a flexible wall dividing the body into a compression chamber and a pressure chamber, means for supplying pressure from the combus tion chamber to the pressure chamber, means supplying the compression chamber with fuel, means exerting pressure on the fuel to flex said wall towards the pressure chamber and provided with a notch, a latch operated by the flexible wall and engageable with the notch for retaining the pressure exerting means inactive when the pressure in the compression chamber exceeds that of the pressure chamber, a spring for normally retaining the latch in an inoperative position, a pipe in communication with the compression chamber for conducting fuel under pressure away from the chamber, and means for causing the spring to exert a greater or less resistance to the movement of the latch. 

